P1573: EVALUATION OF THE EFFICACY OF SARS-COV-2 VACCINATION IN PATIENTS WITH FOLLICULAR LYMPHOMA DURING THE ERA OF THE COVID-19 PANDEMIC
Authors: Евгений Куневич, Irina Martynkevich, Alexey Kuvshinov, Sergey Voloshin, Sergey Sidorkevich
Journal: HemaSphere (2023)

Topic: 30. Infections in hematology (incl. supportive care/therapy) Background: Patients with hematologic malignancies are at higher risk of death from COVID-19. Given the unfavorable prognostic impact of COVID-19 on the course of these diseases, the effectiveness of vaccination against SARS-CoV-2 in patients with follicular lymphoma (FL) was studied. Aims: To evaluate the efficacy of SARS-CoV-2 vaccination and to investigate the impact of COVID-19 on survival in patients with follicular lymphoma. Methods: The study included 123 patients with follicular lymphoma. The average age was 53.6±14.1 years. The ratio of men and women is 1:1.9. Results: 82 (66.7%) patients underwent COVID-19 infection confirmed by PCR. Among them, 35 (42.7%) had minor COVID-19, 31 (37.8%) – moderate, 13 (15.9%) – major, 3 (3.7%) – extreme severe. 45 (36.6%) people were vaccinated against SARS-CoV-2, 30 (66.7%) of whom had COVID-19. The severity distribution in vaccinated patients was consistent with the entire sample. Overall survival (OS) of patients vaccinated against COVID-19 was 94.5% (95% CI: 81.7-98.6), which is significantly higher than that of unvaccinated patients – 62.2% (95% CI: 51.1-73.5), p = 0.023 (Fig. 1A). Disease progression in the first 24 months (POD24) developed in 28 (22.8%) patients. The two-year progression-free survival (PFS) in the vaccinated group was 87.6% (95% CI: 73.2-95.0), and in the unvaccinated group it was 68.9% (95% CI: 57.8-79.2), p = 0.029. The course of the new coronavirus infection did not significantly affect the 2-year event-free survival (EFS), which in vaccinated patients was 80.6% (95% CI: 65.4-90.4.), in unvaccinated patients – 66.1% (95% CI: 55.1-76.9), p = 0.117. The 2-year PFS and EFS were not significantly different in COVID-19 survivors compared to controls, p = 0.141 and p = 0.429, respectively. Neither vaccination against SARS-CoV-2 nor past infection had any effect on overall response rates (ORR). For the “vaccination” factor, the OR was 0.56 (95% CI: 0.12-2.69), p = 0.357, for “COVID-19 infection” it was 1.11 (95% CI: 0.21-5, 77), p = 0.599. Also, both factors were not significantly associated with the frequency of relapses and progressions of FL. In a two-way regression analysis (χ2 = 5.15, p = 0.076), the relative risk (RR) for the “vaccinated” factor in relation to overall survival was 0.21 (95% CI: 0.05-0.93), p = 0.039. For the “past COVID-19 infection” factor, the RR is 1.02 (95% CI: 0.38-2.73), p = 0.963, which confirms the absence of an effect of COVID-19 on the overall survival of patients with FL. Similar data were obtained when predicting 5-year EFS (χ2 = 6.518, p = 0.038). The RR for the factor “vaccination” was 0.4 (95% CI: 0.19-0.83), p = 0.014, for the factor “COVID-19 infection” – 1.03 (95% CI: 0.55-1.91), p = 0.936. Thus, it was confirmed that vaccination against SARS-CoV-2 significantly reduced the likelihood of an adverse event. The worst OS in our cohort was in unvaccinated patients without t(14;18) [FISH], OS was 28.2% (95% CI: 21.5-55.1, median 107.3 months) and was lower than in vaccinated patients without and with t(14;18) [FISH], p = 0.047 and p = 0.161, respectively (Fig. 1B). Summary/Conclusion: It has been shown that COVID-19 does not significantly affect the survival rates of patients with FL, however, vaccination against SARS-CoV-2 significantly improves the prognosis in this group of patients. Unvaccinated patients without t(14;18) are characterized by the worst survival rates, which makes them a separate prognostic group.Figure 1. (A) Overall survival by SARS-CoV-2 vaccination; (B) Overall survival depending on vaccination against SARS-CoV-2 and presence of translocation t(14;18) Keywords: Follicular lymphoma, Vaccination, COVID-19, Survival